I have a similar prob where ive connected to the car. Sometimes it connects and not others. Not too sure just reconnect and then all is good after that until im outside the area of the car.
Still early days and will have more intel in the coming days

Mine keeps searching as well with no luck connecting to my car, this is really annoying. I thought maybe its not compatible with my cars Bluetooth anymore due to the new iPhone 5 with iOS 6 ? My iPhone 4 worked fine with iOS6. I will try a restore from backup and hopefully it works

HI - there is a Bluetooth bug in iOS6, which for me, has rendered Bluetooth in my car through a Pioneers Navigation A/V unit inoperable - it won't pair and the phone settings are all greyed out. I spoke to the Auto Accessories firm who installed my unit in the car and they said that it's common and there is a rather long thread on Apple Forums about that and all other Bluetooth issues with this OS. Here is the url for the thread:

I have similar scenario.
The computer (MBP 2011) will pair with my IP5 - but IP5 will not connect to the MBP - says that "this device is not supported".
Hard to imagine Apple does not support Apple - not even 12 months old.....?
Vehicle can pair with the IP5 and it works. But will not maintain or auto re-connect. Have to go through an install for each use... Painful!